1) Field of the Invention
The present invention relates to a method of detoxifying asbestos, and more particularly, to a method of detoxifying asbestos harmful to a human body and contained in a waste slate at low temperature by using hydrochloric acid and organic acid.
2) Background of Related Art
Asbestos is a term that generally calls fibrous silicate inorganic mineral material produced when the structure of serpentine, hornblende or olivine is changed into the fibrous structure. It is appropriately understood that the asbestos is a natural mineral material produced when the structure of serpentine, hornblende or olivine is changed into the fibrous structure.
In common, as described above, the asbestos is produced in the form of a fibrous assembly, that is, in the form of a bundle. In addition, the asbestos is easily separated from a commonplace dry rock, and split into smaller pieces along a cleavage surface.
The asbestos has excellent tensile force and flexibility and in addition, various excellent properties such as incombustibility. In addition, the asbestos has the merits of being very inexpensive in mining and processing.
Thus, the asbestos products have been used for construction and architecture materials, electronic products, household articles and medicines, and more particularly, used for vehicle components such as vehicle brake lining, a clutch and a gasket. Meanwhile, the asbestos has been utilized for construction materials such as an asbestos slate, an asbestos ceiling material, an asbestos partition, and an extrusion molded cement plate.
The roofs of straw-thatched houses in rural area had been changed into roofs of asbestos slate in a bid of the campaign called “Saemaeul Movement” (New Community Movement, or New Village Movement) in Korea
However, the asbestos, which is a top carcinogen appointed by IARC (International Agency For Research on Cancer) under WHO (World Health Organization), may cause lung cancer, asbestosis, malignant mesothelioma that causes cancer in pleura, or pleura thickening after the incubation period of 20 to 40 years elapses since a person breathed in asbestos dusts.
Specifically, when the asbestos exists in the fibrous structure, the asbestos is fatal to the human body. Thus, taking into account the harmful influence of the asbestos on the human body, the occupation safety and health acts have prohibited the product such as a construction material containing the asbestos of 0.1% or more from being manufactured, imported and used from Jan. 1, 2009. In addition, after 2011, the treatment and movement of all materials containing the asbestos of 1% or more have been illegal.
Currently, as described above, since the asbestos group minerals may lead to serious health effects, when asbestos waste is produced, the asbestos waste should be processed safely and surely. Specifically, in case of waste slates used in many places, a sizable amount of wastes has been still produced through demolition. Although the asbestos wastes are mostly buried to the earth, it is prohibited to bury the asbestos wastes without preprocessing. In addition, since there exist the problems of difficulty in preprocessing, high cost, and the exposure of asbestos as an environmental contaminant, a technique of processing the asbestos wastes scientifically and safely at low cost has been keenly required. Meanwhile, a chemical processing scheme among the schemes of detoxifying asbestos developed until now includes a scheme of removing the fibrous structure by treating the surface of a product containing asbestos with strong acid, and a scheme of heating a product containing asbestos at high temperature for melting. However, according to such a scheme, the strong acid causes a more serious problem than the toxicity of the asbestos itself and the processing cost is greatly increased due to so much energy consumption by heating the asbestos wastes at high temperature. There is a related art for the present invention, such as Korean Unexamined Patent Publication No. 2012-0024103 (published on Mar. 14, 2012) entitled “method of preprocessing serpentine for mineral carbonation”.